Twin prime

#include<iostream.h>
#include<conio.h>
void main()
{
clrscr();
int number,num1=1,count=0,num3=2,previous=2;
cout<<"Enter the upper limit= ";
cin>>number;
cout<<"\nThe twin primes from 1 till " <<number<< " are\n";
while(num1<=number)
{
num3=2;
count=0;
while(num3<num1)
   {
  if(num1%num3==0)
  {
    count++;
  }
  num3++;
  }
  if(count==0)
  {
  if(num1-previous==2)
  {
  cout<<"["<<previous<<","<<num1<<"]"<<endl;
  }
  previous=num1;
  }




  num1++;
  }
  getch();

  }